Let \(Q_{M_X}\)  be the covariation of \(M_X\)  and \(\phi \) , \(\psi \in \mathcal {L}^2(M_X)\) . Then, by adapting the proof of Theorem 2.5 in [1]} to our setting, we get that
\(&\int _0^t \int _{\mathbb {R}^d} \phi (s,x) M_X(ds, dx) \int _0^t \int _{\mathbb {R}^d} \psi (s,x) M_X(ds,dx) \\-\quad & \int _0^t \int _{\mathbb {R}^d} \int _{\mathbb {R}^d} \phi (s,x) \psi (s,y) Q_{M_X}(ds, dx, dy)\) 
